I think the area would be much better for pedestrians if they could make Grand Union skinner from the Rotary to the light at the Partners building. I'm sure that REIT would like the extra space and could possibly pay Somerville for this to happen.
Another idea would be to upgrade the bike lanes to protected bike lanes on the other side of parked cars which would make the street feel smaller and slow down traffic. When I bike protected bike lanes feel a lot safer than unprotected ones, everyone drives in unprotected lanes so it provides little to no benefit versus having no marked bike lanes.
The inner section (near Legoland and AMC) is very pedestrian friendly and has that road closure plaza section, but it's almost like they gave up when designing the outer roadways. I agree with davem that traffic signals would decrease safety, but the road should definitely be narrowed. The travel lanes are huge and they built door zone bike lanes. The right of way is enormous. Even with drivers using caution, an elderly or disabled person will not feel safe crossing in such a long crosswalk.
In a way, it seems as if they even went out of their way to make it horrible for people walking. To pay the meters on the strip mall side of Grand Union you have to walk across a 10ft (often muddy) grass planting strip and that's if you even notice the meters 15ft off in the distance. In the winter, this area is used to store snow from the street and sidewalk and the meters are inaccessible unless you're willing to walk 100+ feet all the way around. I guess you could climb the snow bank too. There is a nice wide sidewalk on this side too, but they cluttered it with benches and meters, making almost half of it unusable walking space.
Sigh. It's just so frustrating.